Retinoblastoma (RB) in Saudi Arabia- Retrospective Comparative Review of a Registry

Results: The EG and LG group had 343 and 430 Rb patients respectively. The incidence of Rb in 1997 and in 2012 was 0.06 and 0.03 per 1,000 live births in Saudi Arabia respectively. The gender distribution was similar. The median age of presentation was 24 (range 11, 39) months in EG vs. 18 (8, 31) months in LG (p <0.001). Incidence of unilateral Rb was 58% [200/343] in EG vs. 56% [278/485] in LG. Positive family history of Rb was <10% in both groups. However, in EG, 120 (35%) parents were first cousins vs. 124 (27%) in the LG (p=0.12). Leukocoria was the most common presentation [71% (n=255) in EG and 66% (n=343) in LG]. Tumor confined to the eye at presentation was more common in the LG group (67% EG vs. 84% LG). Vitreous seeding was more common in LG [62% (n=302) LG vs 45% (n=156) EG; p<0.001]. In the non-surgical group, photocoagulation rate increased in the LG [23.19% (106) LG vs 3.8 %( n=13) EG; p<0.001]. The rate of chemotherapy increased from 4.1% (n= 14) in EG to 14.2% (n=65) in LG (p <0.001). The rate of external beam radiation decreased [37% (n=125) EG vs. 23.4% (n=107) LG]. The rate of extraocular tumor extension was similar in both groups (53.7% EG vs. 51.6% LG; p<0.001). The rate of full thickness choroidal involvement decreased from 13% (n=35) EG to 7.7 % (n=30) LG, (p =0.04). Optic nerve (ON) involvement in LG decreased to 3.4% (n=22) compared to 9.8 %( n=48) in EG (p <0.001).